NMR Studies of Dilute Alloys of Ni in Cu

We have studied the nuclear magnetic resonance of Cu atoms which are near neighbors to Ni atoms in dilute Cu Ni alloys. The experiments were performed at liquid-helium temperatures and at magnetic fields from 6 to 60 kG. The resonances show up as weak satellites to the main absorption of more distant Cu. By varying the magnetic field, we can show that several lines arise from a single shell of neighbors having a quadrupole coupling ν₁=1.1±0.1 MHz, asymmetry parameter η=0.20±0.05, and a magnetic shift ΔHH=-0.27×10^-3. Comparing the quadrupole coupling with estimates made by B\'eal-Monod and Tompa for CuNi by measuring wipe-out number, we conclude the lines arise from first neighbors. The magnetic shift is smaller than we had previously observed for CuCo in almost exactly the ratio of the χJ's of the two impurities, where χ is the impurity susceptibility and J is the s-d exchange coupling.